This invention relates to a labour-saving apparatus for mechanizing, rationalizing and improving in efficiency a series of operations for pouring molten steel through a sliding nozzle at the bottom of a tundish into a mould at a continuous casting facility for sequentially casting.
In general, such operations are conducted not only during the pouring of molten steel but also before and after pouring. Main operations include the exchanging of old for new immersion nozzles following the exhaustion of the immersion nozzle which is connected to the lower end of the sliding nozzle and immersed in the mould, the feeding of a connecting piece into the mould to switchover to a different type or grade of molten steel for the next continuous casting and the feeding of powder for prevention of oxidation of the surface of the molten steel in the mould and for lubrication thereof.
A variety of contrivances have been attempted to eliminate manual operations by mechanizing these operations, however, satisfactory results have not been attained yet.
For instance, the arrangement of the nozzle exchanger described in the Japanese Utility Model Publication No. 58-6606 is dangerous since its operation device runs about over the narrow operation floor, and further more, positioning of the operation device at the sliding nozzle is difficult. Accordingly, it takes a long time to exchange the immersion nozzle. Furthermore, each operation device requires an operator exclusively appointed to its operation.
In the arrangement of the nozzle exchanger described in the Japanese Patent Publication No. 57-44429, all of the tundishes are provided with an exchanger. The exchange operation, therefore, can be made in a relatively short period of time. It has, however, other demerits such as high cost and the necessity to preheat the immersion nozzle to a specified temperature before exchanging the immersion nozzle.
In the arrangement of the connecting piece feeder described in the Japanese Utility Model Publication No. 57-42591, because the immersion nozzle was pierced into the connecting piece, the length of the immersion nozzle has been extra-long. As a result, there were many problems; for example, it was hard to prevent the feeding of powder from interfering with other functions. Additionally, the immersion nozzle could not be replaced until a connecting piece was placed in the mould.
Further, accoding to the above-mentioned prior art, when a variety of operations are to be made on the molten steel pouring operation floor, it is inevitable that some control elements and rotating operation arms are positioned on the operators' side of the overall apparatus to avoid mutual interferences. Such operations on the operators' side of the apparatus are extremely dangerous, and have a fatal defect in the operational aspect that the operators' view of the placement of a connecting piece is hindered.